Uranium-tantalum alloy



United States Patent URANIUM-TANTALUM ALLOY Application November 21, 1945 Serial No. 630,124

2 Claims. (Cl. 75-1221!) No Drawing.

The present invention is concerned with uranium base alloys and more particularly relates to uranium base alloys containing tantalum.

One object of the present invention is to produce uranium-tantalum alloys which are useful in neutronic reactors.

Still another object of this invention is to so improve the physical properties of uranium and uranium alloys as to enhance the corrosion resistance thereof and render the same eminently useful for various purposes for which uranium and uranium alloys now in use are not satisfactory and efiective.

Other objects of the present invention will be apparent from the following description, taken in connection with the appended claims.

The present invention is directed to new and novel uranium-tantalum alloys which have certain extremely desirable characteristics. While these uranium-tantalum alloys may vary somewhat in their physical characteristics, they will be generally characterized by improved corrosion resistance. Alloys having especially good properties include those containing about 0.5 to 15 percent by weight tantalum, the balance being uranium. For example it was found that a uranium-tantalum alloy containing 4 percent by weight tantalum was approximately 500 times more resistant to the efiect of boiling water than pure uranium. About the same results were obtained with an alloy containing 8 percent by weight tantalum. Other alloys containing as much as 95 percent by weight of tantalum, the balance being uranium are found to have advantageous properties.

These new uranium-tantalum alloys may be conveniently prepared by melting uranium with tantalum strips in a refractory crucible, for example in a beryllia ICC crucible. The uranium and tantalum metals should be melted in the absence of oxygen and moisture, as for example in vacuo or in an inert atmosphere. When the temperature of the uranium is raised to about 1800 C. to 2000 C., the tantalum strips are dissolved and the alloy is formed.

Another convenient method of preparing these new uranium-tantalum alloys comprises pressing powdered uranium and tantalum metals together and then sintering, at about 1800 C., and then fusing them in an atomic hydrogen torch.

By means of thermal and microscopic analysis it was found that the uranium-tantalum system contains no eutectics and that no intermetallic compounds are formed. It was also found that tantalum is partially soluble in solid gamma uranium. Further studies showed that the solidus rises from about 1130 C. (the melting point of pure uranium) to about 1175" C. at about 10 percent by weight of tantalum where a peritectic reaction occurs forming a liquid which contains less than 10 percent by weight of tantalum and substantially pure solid tantalum. The temperature of the gamma-beta transformation for uranium is lower in alloys containing tantalum than in pure uranium. On the other hand the temperature of the beta-alpha transformation for uranium is substantially unaffected in uranium-tantalum alloys.

It will be apparent to those skilled in the art to which this invention pertains that various modifications may be made without departing from the principles of the invention as disclosed herein, and thus it is not intended that the invention should be limited other than by the scope of the appended claims.

What is claimed is:

1. A uranium-base alloy consisting of from 85.0% to 99.5% of uranium and from 0.5 to 15% of tantalum, said alloy being corrosion-resistant.

2. An alloy containing 4% of tantalum and the remainder consisting of 96% of uranium.

References Cited in the file of this patent UNITED STATES PATENTS 969,064 Kuzel Aug. 30, 1910 1,449,338 McCurdy Mar. 20, 1923 1,701,299 Engle Feb. 5, 1929 1,741,953 Ramage Dec. 31, 1929 1,831,241 Grenagle Nov. 10, 1931 

1. A URANIUM-BASE ALLOY CONSISTING OF FROM 85.0% TO 99.5% OF URANIUM AND FROM 0.5 TO 15% OF TANTALUM, SAID ALLOY BEING CORROSION-RESISTANT. 